Electrical condenser and the like



x v x June 28, 1932. JOFFE 1,864,828

ELECTRICAL CONDENSER AND THE LIKE Filed May 15, 1926 Patented June 28,1932

UNITED STATES PATENT OFFICE J'OFIE, OI LENINGRAD, RUSSIA, A SSIGNOB TO INDUSTRIAL RESEARCH COKQ rm, OF E, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS I ELECTRICAL CONDENSER AND THE m Application and Kay 15, 1926. Serial at. 100,214.

My present invention relates to capacities, such as condensers, variable and fixed, and the like, and aims to devise devices of the general character specified which are simple in construction, easy and convenient to fabricate and to awemble, and which arecharacterized by their simple construction, their accuracy and reliability in use, andtheir reslstance to rupture even when highly charged.

In the accompanying specification I shall I illustrated the aforesaid illustrative embodi-' describe and in the annexed drawing more or less diagrammaticall illustrate, an illustrative embodiment of t e present invention. It is however, to be clearly understood that my invention is not limited to the specific form thereof herein shown and described for purposes of illustration only.

Referring to the drawing, wherein I have ment of the present invention:

Fig. 1 of the drawing shows, more or less diagrammatically, in side elevation, a simple I embodiment of the type of capacity orcondenser constructed in accordance with the principles of the present invention;

F i 2 is a longitudinal sectional view of the evice shownin Fig. 1 of the drawing,

more particularly to t e drawing illustrating the same, 10 and 11 indicate layers or films of conductive material, such as layers or films of aluminum which may be of any desired thickness. These conductive plates or films perform the usual function mthe condenser or ca acity of servingas the terminal plates to w 'ch the poles of the source of high-tension or other current may be connected to charge the condenser or capacity.

Interposed between the conductive plates or films 10 and 11 is a layer or film preferably of a non-crystalline polarizable material of a dielectric semi-conductive or similar character. This layer or film of polarizabIe dielectric or like material has been generally designated by reference character 20.

The material.20 is not an ordinary dielectric, insulation or like material, but is rather a non-crystalline material capable of being polarized so as to serve as a storer or accumulator -of a charge of electric current havin a polarity the magnitude and character 0 which depends upon the charge impressed upon the positive plate or terminal, here designated by reference character 10, In a copending application of mine filed October 28,

1925, Serial No. 65,262, and entitled Utiliz- 1 ing the polarization of dielectric substances traversed by electric currents, I have set forth the basic principles of the property of the class or type of non-crystalline dielectric substances capable of bein polarized and capable, for this reason, of being adapted for the purposes of the present invention. The present application is a continuation in part of the earlier filed application just referred to. As set forth in such earlier filed copendingapplication I have previously discovered, as described b me in the article published together with rof. W. C. Rontgen (Analen der Physik, IV, volume 72, page 472) that dielectric crystals, that is, crystals of dielectricsubstances, are polarized upon passin thro ugh the same a current at a potential 0 abo ut or exceeding ten thousand volts. Under such conditions, the electromotive force of the polarization approximates the applied potential.

My investigations have shown that this polarization apparently takes place only in a. thin layer of stratum bordering upon the crystal at the surface of the cathode. Moreover, it comprises a condition of ionization. In contradistinction to the ordinary molecu-' lar stress extending uniformly through a dielectric irrespective of its thickness, this polarization is therefore a surface or ionic po larization. Apparently, the thickness of the material of which the dielectric crystal is made does not have any appreciable influence on the polarization. However, in many instances additional thickness (in addition to the thickness of the polarized layer) is not only useless but objectionable as for example in high fre uency circuits. onsequently an important eature of the invention consists in confining the thickness of the dielectric to a dimension comparable to the thickness of the aforesaid polarization.

I have discovered, as a result of further extensive researches in this and related fields, that other dielectric substances, of a non-crystalline character, and even semi-conductors, have yielded the wholly unexpected result of becoming similarly polarized upon passing therethrough a current of about or exceeding one or two thousand volts, this unexpected result being obtained when the consistency of such non-crystalline dielectric substances and semi-conductors is tough or sufficiently strong or solid.

For example, I have discovered that satisfactory polarization eflects may, under such conditions, be obtained with such substances as calcium carbonate, aluminum phosphate, aluminum oxide, cement, linseed-oil varnish, etc.

While for an insulation for high-tension transmission lines and the like I prefer that the non-crystalline polarizable material shall comprise a linseed oil varnish, made as set forth on later in this specification, and characterized by a relatively low specific capacity and a relatively high specific conductivity, such material may, however, also be used for the purposes of the present invention in the construction of a capacity or condenser made in accordance with the principles of the present invention. Likewise, while for the purpose of an accumulator or storer of hightension current made in accordance with the principles of my earlier filed copending application referred to above, I prefer to use a non-crystalline inorganic substance like precipitated calcium carbonate or this same substance in the form of the material known as mother of pearl, characterized by a relatively high specific capacity and a relatively high specific conductivity, I may use this material also for the purposes of the present invention in the construction of a capacity or condenser made in accordance with the principles of the present invention.

I prefer, however, for the specific purposes of t e present invention, to use a material characterized by a relatively high specific capacity and a relatively low specific conductivity, such as the material known as boron trioxide. This material is remarkably well suited for use in capacities or condensers made in accordance with the principles of the present lnvention.

In the case of a linseed oil varnish, for example, while a layer 0.01 mm. in thickness, for an average variety of such varnish, may be ruptured by the sudden application of an electric tension of one thousand volts, if the electric tension is gradually. built up over a substantial period of time, as from about one-half to about one second, more or less, such a layer will stand an electric tension of ten thousand or even fifteen thousand volts before being ruptured.

.As an example of such a linseed oil varnish, I may mention a linseed oil varnish made up of linseed oil, containing from about 1 to about 3 per cent. its weight of a suitable drier or oxidizer, dried at an elevated temperature, as from about 100 to about 200 centigrade. For example, where the drying takes place at about 180 centigrade, should be continued for from about two to abaut three hours,

In order to serve the purposes of the present invention most successfully, it is desirable, even necessary, that the layer or film of the linseed oil varnish be of substantially uniform or even thickness. For this purpose, I prefer that the drying take place on a layer of mercury or other suitable heavy liquid on which the varnish may float during the drying operation, the varnish being preferably dissolved for this purpose in a suitable solvent, such as nitrobenzol.

Such a layer of linseed oil varnish, mother of pearl, or boron trioxide, preferably the latter, will be found to have a capacity for Faradic current up to five thousand, ten thousand, or even fifteen thousand, volts for a thickness of the material of an order of about 0.01 mm. Furthermore, if thevoltage is applied gradually and over an appreciable period of time, as from about one-half to about one second, this thin layer of non-crystalline polarizable material in accordance with the principles of the present invention will not be ruptured by such voltages, whereas if the voltage were suddenly applied it might be ruptured by a voltage as low as one thousand volts.

The action of the charge is difficult to ascertain, but it would appear as if the material is polarized or ionize thus causing the material to receive an appreciable charge under high tension and adapting it, therefore, for a condenser or capacity characterized by its remarkable capacity, its great strength, its accuracy, and its resistance to rupture.

As already stated, the outer conducting plates 10 and 11 may consist of aluminum or other suitable metallic or other conductive substance. Furthermore, in place of the materials already mentioned as being suitable for use as non-crystalline polarizable substances for the purposes of the present invention, certain organic materials, such as colloidal calcium compounds, or certain inorganic materials, generally of a colloidal character, such as gum or resins, may be employed for the purpose of the present invention.

In concluding the description of the aforesaid illustrative embodiment of the present invention, it may be desirable to indicate the following methods which are suitable for the manufacture of thin dielectric layers suitable for embodiment in the various high-tension polarization devices described above:

conductive substance may be formed b electrolysis using a further chemical or ectro- 5 chemical reaction, if necessar to complete the formation of the desire dielectric or semi-conductive substance.

(4) The desired dielectric or semi-conductive substance may be formed by cathodic or mechanical dispersion, which latter is also :imed the spraying or spouting meth- (5) The desired layer of dielectric or semiconductive substance may be formed by sepa 5 ration from a solution or from a colloidal solution.

(6) Finally other methods by which thin layers of anysuitable material are produced,

particularly such mechanical methods as rollmg, pressin or the like, may be used for producing the esired dielectric orsemi-conductive layers.

The results of the present invention are numerous and of great practical importance.

By means of the polarizabl dielectric or like substances of the present invention, especially in non-crystalline condition such as the linseed oil varnish, mot'ncr oi pearl, and boron trioxide described above, and the arrangement of such material in one or more layers together with one or more intervening or surroundin or intervening and surrounding, layers 0 metal or other suitable conducting materials, the alternate members of which may be connected to one pole and the remaining members of which may be connected to the other pole of a source of hightension or other current, it is possible in a simple and highly efiicient manner to construct .a condenser or capacity, either variable or fixed, which embodies one or more la ers of one or more of the various non-cryst ine dielectric or like substances of the present in: vention. The resulting capacities or condensers are characterized by their simplicity in construction, their dependability, their remarkably high capacity and their resistance to rupture. L

Other advantages and superiorities of the capacities and condensers of the present in-' vention will be readily a parent to those skilled in the art to whic the present invention relates.

Referring now to Figs. 3 to 8 inclusive,

Fig. 3 show'sthe distribution of the charge where the wire carries positive electricity, Fig. 4 showing the distribution of the charge where the wire carries negative electricity, Figs. 5 and 6 illustrating the gradients for'these respective types of transmission. Figs. 7 and 8 show the gradients forthese two types of transmission where the dielectric or semi-conductive substance consists of borax, boron trioxide or borax glass where the polarization produces charges of both signs.

What I claim as my invention is:

1. A capacitor comprising a plurality of electrically conductive elements and a layer v of semi-conductive polarizable material comprising boron trioxide interposed between each pair of said electrically conductive elements oif which a layer of a thickness of an order of about 0.01 mm. has a resistance to rupture up to about a volt-age of an order of abo tten thousand volts under graduated loa 2. A capacitor comprising a plurality of electrically conductive elements and a layer of semi-conductive non-crystalline olarizable material comprising boron trioxlde interposed between each pair of said electrically conductive elements:

3. Acapacitor comprising a plurality of electrically conductive elements and interposed polarizable material comprising boron trioxide.

4. A capacitor comprising a plurality of electrically conductive elements and a layer of semi-conductive non-crystalline polarizable material comprising boron trioxideinterposed between each pair of said electrically conductive elements ofwhich a layer of a thickness of an order of about'0.0 1 mm. has a resistance to rupture up to about a voltage of an order of about ten thousand volts under graduated load.

5. A capacitor comprising a plurality of electrically conductive elements and inter posed olarizable material comprising boron trioxi e of which a layer of a thickness of an order of about 0.01 mm. has a resistance to rupture up to about a voltage of an order of about ten thousand volts under graduated loa 6. A capacitor comprising a plurality of electrically conductive elements and a layer of semi-conductive polarizable material comprising boron trioxide interposed between each pair of said electrically conductive elements.

7. The method of producin dielectric capacitor material which comprises subjecting a thin layer of semi-conductive polarizable material of a thickness of an order of'about .01 mm., to a gradually increasing voltage upmaterial to a voltage and gradually increasing the value of said volta e from zero up to a potential gradient of a out 1,000,000 volts per centimeter, the thickness of said layer being considerably less than 1 mm.

9. A capacitor including a thin layer of semi-conductive polarizable material of a thickness of an order of about .01 mm. said material having a thin polarized layer formed upon one surface thereof.

10. A capacitor com rising a thin layer of semi-conductive polarizable material, said layer being polarized upon one surface thereof, the insulating strength of said layer being concentrated in said olarized layer so that a voltage which would produce breakdown across an unpolarized layer of the same thickness is insufiicient to cause breakdown.

11. lhe method of producing dielectric capacitor material which comprises-subjecting a thin layer of semi-conductive, polarizable material of a thickness of the order of .01 mm. during a period not less than the order of a half a second to a gradually increasing voltage up to the order of about 1000 volts, the said upper limit not being attained until the end of said period.

12. The method of producing dielectric capacitor material which comprises subjecting Y a sheet of semiconducting polarizable material of a thickness considerably less than one millimeter to a gradually increasing voltage, rendering a layer of said sheet polarized and able to withstand a voltage that is sufficient to break down an unpolarized sheet layer of the same thickness.

In testimony whereof. I have signed my name to'this specification this 20th day of ABRAHAM JOFFE.

February, 1926. 

